The present invention relates to a transversal filter with at least one analogue shift register and additionally relates to a process for the operation thereof.
Previously known transversal filters of the type referred to in the introduction are constructed with charge-coupled shift devices (CCDs), and employ either the split electrode principle or the CCD possesses parallel outputs at which the signal can be withdrawn. These known designs are described for example in the publication "Charge Transfer Devices" by Tompsett N.F., Sequien C.H. in Academic Press Inc. New York, San Francisco, London, 1975. In these designs the desired filter function is realized as pulse response, i.e., a short pulse as input signal produces the desired pulse response as output signal at the output end by dividing the individual electrodes of the CCD in the case of the split electrode principle and by evaluating the parallel outputs in the case of the other principle.
With the above described split electrode principle, the output signal is formed from the difference between two high voltages which presents considerable circuitry problems. A further problem consists that under the most unfavorable circumstances, small charge parcels are distributed over large areas. In the process employing parallel outputs, floating gate amplifiers are required which, due to their complicated construction, require for example a multi-layer metallization and consequently entail problems in production and further problems during operation, for example as a result of attenuation due to voltage division.